This invention relates to an improved check valve plate assembly for use in scroll compressors which, while providing a desirable seal, is better adapted to withstand the stress imposed during the operation of a scroll compressor than the known valve plate assemblies.
Scroll compressors have become widely utilized in refrigerant compression applications. Since scroll compressors have greater efficiency than many types of compressors, they are desirable for many applications. However, scroll compressors also present many design challenges.
One challenge occurs at shutdown where a relatively large volume of compressed gas can move back through a discharge port and between the scroll compressor components. This can cause the scroll components to be driven in a reverse direction. To accommodate the issue of return gas, the scroll compressor is typically provided with a discharge valve which limits the amount of gas which moves between the scroll compressor components. It is desirable that the discharge valve forms a suitable seal with its respective valve seat. The discharge valve presented in the prior art provides such a seal.
One known discharge valve plate is stamped from relatively thin steel reed material, preferably having a generally uniform thickness of less than 0.03 inch and most preferably having a thickness of 0.015 inch. During operation, the prior art discharge valve pivots along an axis defined by pins that are formed by rolling laterally spaced ears that are integral to the valve plate and formed when the discharge valve plate is stamped or cut. This type check valve is disclosed in pending U.S. application Ser. No. 09/056,066, filed Apr. 6, 1998.
During the stamping procedure, notches are cut adjacent to the laterally spaced ears to enable them to be rolled into the pins that permit the valve plate to pivot. However, the notches cause local cross sectional area reduction on the formed pins and weaken their bending strength. Further, these notched areas of the valve plate undergo significant stress during scroll compressor operation and have been found to crack at these weaker areas.